The present invention relates to intraocular implants for implantation in the human eye and, in particular, it concerns intraocular implants having a combination of optical elements such as lenses, lenses coated as mirrors, mirror, magnifying element, prisms of various forms and semi transparent mirrors.
By way of introduction, there are many ocular diseases where the patient's vision can be improved using optical implants into the eye. Macular degeneration (hereinafter, “AMD”) is one if these disorders. Eyes suffering from AMD are damaged in the center of the visual field and the patients, usually the older population, maintain their peripheral vision, but lose their central vision. These patients are not blind. They can navigate in their surroundings and they do not stumble over chairs or other furniture. However, when they need their central accurate vision they see a black central spot and they are therefore unable to read, write, drive, work on a computer, recognize faces. They even have difficulty eating. At the final stage of this disease the patient becomes legally blind. Although AMD is the most common central retinal degeneration disease (about 25–30% of the population over 75) there are many other diseases that cause damage to the central or peripheral visual field, for example, but not limited to, diabetic retinopathy, ocular vascular accident, retinal dystrophies (such as Retinitis Pigmentosa).
In a normal eye, the central vision is used for focused vision, for example, for reading. The extraocular muscles move the globe of the eye so that the image of an object being viewed always appears on the point of central vision that occupies only a small fraction, less than 10%, of the retina, known as the macula. The bulk of the retina is used for peripheral vision, which serves primarily for orientation in space. The visual acuity of this bulk area is not as sharp as the macula. Thus, central vision provides a relatively small field of view with very high resolution for perception of details, while peripheral vision provides a wide field of view with relatively low resolution, providing sufficient information for navigation and detection of targets of interest.
Of relevance to the present invention is U.S. Pat. No. 4,759,761 to Portnoy, which teaches a catadioptric intraocular lens containing interior mirrored surfaces forming a folded telescope. The lens of Portnoy patent suffers from many limitations similar to those of an Intra-Ocular Telescope (hereinafter “IMT”). IMT devices are taught by U.S. Pat. Nos. 5,354,335 and 5,392,202 to Lipshitz, et al. A shortcoming of the lens of Portnoy is that it does not preserve nor permit peripheral vision because the mirrors cover the entire pupillary aperture. Therefore, the device of Portnoy produces a limited magnified central visual field only. Furthermore, the device of Portnoy is not structured for use with other diseases, such as diabetic maculopathy, retinitis pigmentosa or advanced glaucoma, as the mirrors cover the entire pupillary aperture, the natural peripheral visual field is obscured and it is therefore almost impossible to examine the retina or treat it. Also the IMT devices as well as the device of Portnoy, (which was never built or used in clinical practice) can only be implanted into one eye as one eye needs to be used for central vision and the other eye for peripheral vision as the implant does not allow both visions in one eye. This leads to several limitations including: anisoconia (difference in image size between the eyes), a difference in the angular velocity of moving objects between the eyes and the need for prolonged rehabilitation due to the two eyes having different visual performance (one eye for a magnified central visual field and the other for the normal peripheral visual field). Furthermore, if in the future, one eye severely deteriorates the patient cannot function with only one eye as he can either use the one eye for central vision or peripheral vision, but not both.
Copending U.S. application Ser. Nos. 10/108,458 and 10/316,066 to Lipshitz, disclose an optical implant that not only magnifies the central visual field but also preserves at least some of the peripheral vision, thus, the patient who has this device implanted into his eyes not only sees a magnified image in the central visual field but also has at least some peripheral vision in the same eye. According to these co-pending patent applications, the device can be implanted in both eyes thus eliminating many problems that are created by the IMT and the Catadioptic Lens taught by Portnoy
There is therefore a need for an intraocular implant for treatment of defects in central vision, including AMD and other disorders of the macula, as well as increasing the central visual field while preserving at least some peripheral vision, and other disorders of vision, such as regular cataracts, while preserving the natural unchanged peripheral visual field, devoid of the above limitations.
Additionally, it would be desirable to have a device that permits a full normally sized visual field with a magnified central image for seeing precise objects such as for reading while preserving peripheral vision, without magnification, or with very small amounts of magnification, as well.